Drug use and street crime in Miami: an (almost) twenty-year retrospective

Researchers at the University of Delaware have been conducting field studies of drug use and crime in Miami, Florida, since 1977. This paper reviews this research and its contributions to understanding drugs-crime relationships. Early studies tested mechanisms for accessing street populations of heroin users and assessing the nature and extent of their drug use and criminality. Subsequent studies targeted a variety of crime-involved heroin and cocaine users, including women as well as men, serious delinquents, adolescent and adult crack users, and cocaine users in treatment as well as on the street. Major findings include the low risk of arrest for income-generating crimes committed by heroin users, and the prevalence of HIV-risk behaviors among both serious delinquents and women crack users. Analyses consistently show the critical importance of sample characteristics in research on drug use, including age, cohort, and street-versus-treatment status.     

Shift in sodium chloride sources in past 10 years of salt reduction campaign in Japan

We compared the prevalence of injuries requiring medical treatment in the general population, in cocaine users and in heroin users, and we studied the factors associated with the occurrence of injuries in these groups, using data from two interview surveys carried out in 1993 in Spain: the National Health Interview Survey, a national representative sample of the non-institutionalized general population, and a survey of a non-probability sample of heroin or cocaine users selected from the community. The subjects included in the study were persons 16-40 years of age in urban areas: 4261 persons from the general population, 369 cocaine users and 215 heroin users. The annual prevalence of injuries requiring medical treatment was 7.9 percent in the general population, 10.8 percent in cocaine users and 35.2 percent in heroin users. There was a statistically significant positive association of injury occurrence (1) among the general population: with male sex, alcohol use, use of tranquillizers/sleeping pills, and the use of antidepressants or stimulants; (2) in cocaine users: with the use of opiates other than heroin; and (3) in heroin users: with alcohol use, the use of tranquillizers/sleeping pills, and the injected route. The only statistically significant negative association was with the amount of cocaine consumed among heroin users. The results suggest that other psychoactive substances besides alcohol are positively associated with injury occurrence, and that cocaine use may contribute to a reduced risk of injuries associated with the use of depressants (alcohol, tranquillizers, heroin).     

The role of drug use in a conceptual model of intimate partner violence in men and women arrested for domestic violence.

In a previous study, alcohol problems in perpetrators and their partners contributed directly and indirectly to intimate partner violence (IPV), even after including other correlates of violence in the model (G. L. Stuart et al., 2006). The present study extends these findings by examining the role of illicit drug use. We recruited 271 men and 135 women arrested for IPV and used structural equation modeling to examine the data. Results showed that drug use, as reported by the perpetrators, was a stronger predictor of IPV than were alcohol problems in perpetrators and their partners. Arrested males' marijuana use and stimulant use (i.e., cocaine and amphetamines) were associated with perpetration of IPV, and their report of their female partners' stimulant use was associated with her violence perpetration. In arrested women, specific substances used did not predict violence perpetration beyond other model variables; however, female perpetrators' report of male partners' stimulant use predicted male psychological and physical aggression, after controlling for other variables. These results provide further evidence that drug problems by both partners may be important in the evolution of aggression. Implications for batterer intervention programs are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social context and perceived effects of drugs on sexual behavior among individuals who use both heroin and cocaine.

Researchers have identified the association between the use of cocaine and sexual behavior as an important risk factor for HIV infection and have attempted to elucidate the nature of this association. Several lines of research have suggested that facilitation of sexual behavior during intoxication with cocaine may be because of the direct pharmacological effects of the drug (e.g., increase in sexual desire), whereas others have pointed to the importance of factors related to the context of drug use (e.g., opportunities for sexual behavior, expectations about the effects of the drug, social norms). The present study explored the perceived effects of cocaine and heroin on sexual behavior, as well as the social context of drug use as a function of drug type (cocaine vs. heroin), among 46 inner-city drug users who reported a history of regular use of both crack cocaine and heroin. Results indicated that compared to heroin, cocaine had deleterious effects on participants' perceived sexual desire and performance. Despite such deleterious effects on sexual behavior, cocaine was more frequently used with an intimate partner than heroin. Furthermore, participants did not differ in the extent to which they used the two drugs in other social contexts (e.g., with friends, family, or neighbors). These preliminary results suggest that the relationship between cocaine and sexual behavior, especially among long-term cocaine users, may be facilitated by opportunities for sex that exist in the context of cocaine use, rather than by the pharmacological effects of the drug. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differences in impulsivity and risk-taking propensity between primary users of crack cocaine and primary users of heroin in a residential substance-use program.

Crack cocaine use is more associated with impulsivity and a propensity to take risks than heroin use, yet no studies have examined this relationship in the absence of acute drug effects. The current study examined impulsivity (using the Delay Discounting Task) and risk-taking propensity (using the Balloon Analogue Risk Task) across independent groups of primary crack cocaine users with minimal heroin use (n=16) and primary heroin users with minimal crack cocaine use (n=11) in residential treatment, with all participants drug abstinent during participation. Crack cocaine users evidenced greater levels of impulsivity and risk-taking propensity, with only the difference in impulsivity persisting after controlling for age and gender. These data hold potential theoretical importance in understanding differences between crack cocaine and heroin users, as the findings cannot be attributed solely to acute pharmacological drug effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Illicit drug use among Mexicans and Mexican Americans in California: the effects of gender and acculturation

AIMS: To examine the effects of gender and acculturation on illicit drug use among the Mexican-origin population in California. DESIGN: The 3012 subjects between 18 and 59 years of age were selected under a stratified, multi-stage cluster sampling method. SETTING: Fresno County in California is primarily agricultural, with only one metropolitan area. Over 30% of the total population of 764,800, are Hispanics, of Mexican origin. MEASUREMENTS: A modified version of the World Health Organization's Composite International Diagnostic Instrument (WHO-CIDI) was used to ascertain drug use. Respondents were considered drug users if they had ever used marijuana, cocaine, hallucinogens, heroin or inhalants. Acculturation was measured with a Likert scale, assessing English vs. Spanish language preference. Other covariates of interest were nativity and place of residence. FINDINGS: Men had higher rates of use than women for every drug (men = 46.3%, women = 23.2%). Urban rates were higher than rural rates, for both women (urban = 32.8% vs. rural = 16.6%) and men (urban = 57.0% vs. rural = 36.8%). In logistic regression models, men were more likely than women to have ever used illicit drugs or inhalants (adjusted OR = 4.8), cocaine (adjusted OR = 5.3) or marijuana (OR = 4.3). However, the combined effect of United States nativity and acculturation, on drug use, was greater among women (adjusted OR = 29.3) than among men (adjusted OR = 7.4). The effect of acculturation was stronger among urban, than among town or rural residents. CONCLUSIONS: Acculturation and United States nativity are risk factors for illicit drug use among Mexican origin men and women. However, women have increased vulnerability compared with men. Findings reinforce the need for culturally based public health interventions.     

A randomized controlled trial of the therapeutic workplace for community methadone patients: A partial failure to engage.

The Therapeutic Workplace is an employment-based treatment for drug addiction that uses wages for work to reinforce drug abstinence. The Therapeutic Workplace has promoted abstinence from heroin and cocaine in treatment-resistant mothers in methadone treatment. This study attempted to replicate that effect in crack cocaine users recruited from community-based methadone programs. Participants were randomly assigned to a Therapeutic Workplace (n=22) or usual care control (n=25) group. Therapeutic Workplace participants were invited to work in the workplace and earn vouchers every weekday for 9 months contingent on documented opiate and cocaine abstinence. The two groups did not differ significantly on measures of cocaine or opiate use collected during study participation. Daily attendance and urinalysis results of the Therapeutic Workplace group were analyzed, and only 7 of the 22 participants initiated consistent periods of abstinence and workplace attendance. Two individuals gained access to the workplace on a few days, and 9 participants attempted to gain access to the workplace but never provided a drug-negative urine sample. Possible reasons for differences between the current study and the previous Therapeutic Workplace study are considered. Procedures that increase participant contact with the Therapeutic Workplace and its reinforcement contingencies might increase the likelihood of these individuals being successful in the treatment program. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synergistic elevations in nucleus accumbens extracellular dopamine concentrations during self-administration of cocaine/heroin combinations (Speedball) in rats

The abuse of cocaine/opiate combinations (speedball) represents a growing trend in illicit drug use. Delineation of neurobiological substrates mediating the reinforcing effects of the combination may increase our knowledge of reinforcement mechanisms and provide useful new information for the development of pharmacotherapies. Several studies suggest dopaminergic innervations of the nucleus accumbens (NAc) have a central role in the brain processes underlying drug reinforcement. The present study was undertaken to determine the relationship between the self-administration of cocaine/heroin combinations and NAc extracellular dopamine concentrations ([DA]e) using in vivo microdialysis and microbore high-pressure liquid chromatography. Rats were assigned randomly to one of three groups to self-administer i.v. cocaine (125, 250, and 500 micrograms/infusion; n = 5), heroin (4.5, 9, and 18 micrograms/infusion; n = 5), or cocaine/heroin combinations (125/4.5; 250/9, and 500/18 micrograms/infusion; n = 4) under a fixed ratio (FR) 10: 20-s time-out schedule of reinforcement/multicomponent dosing session. After stable rates of responding were engendered and maintained, microdialysis samples were collected in 10-min intervals during the self-administration session. Self-administration of cocaine/heroin combinations produced synergisitic elevations in NAc [DA]e (1000% baseline) compared with cocaine (400% baseline) and heroin (not significantly different from baseline levels). Neither the number of infusions nor the interinfusion intervals was significantly different between the groups across the self-administration session. Moreover, cocaine concentrations were not significantly different between the cocaine and cocaine/heroin groups. These results demonstrate that heroin interacts with cocaine to produce synergistic elevations in [DA]e, providing a neurochemical basis for understanding the abuse liability of cocaine/opiate combinations.     

Using latent-variable models to analyze smoking cessation clinical trial data: An example among the methadone maintained.

The relationship between tobacco and illicit drug use was examined among 166 methadone-maintained persons participating in a smoking cessation intervention. Latent-growth latent-variable models showed a significant relationship during treatment between rates of change in heroin and rates of change in tobacco use, with increased heroin use corresponding with increased tobacco use. Although levels of cocaine use were related to levels of tobacco use, there was no significant relationship between the rates of change of the 2 substances. A more traditional longitudinal structural equation model demonstrated a significant relationship between more heroin use during treatment and negative smoking cessation outcomes at 6-month follow-up. Findings demonstrate the utility of latent-growth models for analyzing short-term clinical trial data and strongly suggest that successful smoking cessation in this population requires a concurrent focus on reducing heroin use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of other maternal variables on the relationship between maternal virus load and mother-to-infant transmission of human immunodeficiency virus type 1

To assess the relationship between maternal human immunodeficiency virus (HIV) type 1 RNA level, other important covariates, and mother-to-infant (vertical) transmission of HIV-1, third trimester repository specimens from 160 HIV-1-seropositive women enrolled in the Mothers and Infants Cohort Study between 1986 and 1991 were assayed in batch for HIV-1 RNA. A significant association between peripheral blood HIV-1 RNA level and vertical transmission remained after controlling for CD4 cell level, duration of ruptured membranes, "hard" drug (cocaine and heroin) use, and frequency of sexual activity during pregnancy. However, the association was attenuated among women with advanced HIV infection and those with a high frequency of sexual activity during pregnancy. In these settings, interventions that target risk factors other than virus load may be particularly important for preventing vertical transmission of HIV-1.     

Drug-induced reinstatement of heroin- and cocaine-seeking behaviour following long-term extinction is associated with expression of behavioural sensitization

The present study was designed to evaluate the relationship between reinstatement of drug-seeking behaviour following long-term extinction of intravenous (i.v.) drug self-administration (an animal model for craving) and long-term behavioural sensitization. Rats were allowed to self-administer heroin (50 microg/kg per inj., 14 daily sessions), cocaine (500 microg/kg per inj., 10 daily sessions) or saline. Following a 3-week extinction period, reinstatement tests were performed to evaluate priming effects of amphetamine, cocaine and heroin on nonreinforced drug-seeking behaviour. In addition, the occurrence of long-term behavioural sensitization in rats with a history of heroin or cocaine self-administration was determined. Heroin-seeking behaviour was reinstated by heroin (0.25 mg/kg), amphetamine (1.0 mg/kg) and cocaine (10 mg/kg). In addition, animals with a history of heroin self-administration displayed locomotor sensitization to both heroin and amphetamine. Cocaine-seeking behaviour was reinstated by cocaine and amphetamine, but not by heroin. Interestingly, locomotor sensitization to amphetamine, but not heroin, was observed in animals with a history of cocaine self-administration. In other words, the induction of drug-seeking behaviour following a prolonged drug-free period was found to be associated with the expression of long-term behavioural sensitization. These data provide experimental evidence for a role of behavioural sensitization in the incentive motivation underlying drug-seeking behaviour. If drug hyperresponsiveness would indeed be a crucial factor in drug-induced craving in human addicts, pharmacological readjustment of the neuroadaptations underlying drug sensitization may prevent relapse to drug use long after detoxification.     

Comparison of heroin and cocaine concentrations in saliva with concentrations in blood and plasma

Saliva is an alternate biological matrix for drug testing that has several advantages over more traditional fluids such as blood and urine. Collection is rapid, noninvasive, and relatively easy to obtain. Several reports have detailed the appearance of drugs of abuse in saliva, but few have compared the excretion profiles of drugs administered by different routes. In this study, subjects were administered three smoked and three intravenous doses of heroin in an ascending dose design. Blood and saliva were collected periodically after drug administration and analyzed by gas chromatography-mass spectrometry (GC-MS) for heroin, 6-acetylmorphine, and morphine. In a second study, subjects were administered a single, smoked dose of 40 mg cocaine base and an intravenous dose of 44.8 mg cocaine HO on separate occasions. Plasma and saliva were collected and analyzed by CC-MS for cocaine, anhydroecgonine methyl ester (AEME), and seven additional metabolites. Heroin and 6-acetylmorphine were detected in the first saliva sample collected (2 min) following drug administration by both routes. Peak heroin concentrations were achieved quickly, between 2 and 5 min after intravenous administration and at 2 min after smoke heroin. Peak heroin concentrations in saliva after smoking heroin base ranged from 3534 (2.6 mg) to 20,580 ng/mL (5.2 mg), and after intravenous administration, concentrations ranged from 6 (10 mg heroin HCl to 30 ng/mL (12 mg heroin HCl. Saliva concentrations of heroin declined rapidly after intravenous administration, reaching the limit of sensitivity of the assay (1 ng/mL) by 60 min. Heroin concentrations in saliva after smoking declined slowly; detection times ranged from 4 to 24 h. Cocaine was the major analyte detected in saliva and plasma after smoked and intravenous administration. Peak saliva cocaine concentrations after intravenous administration ranged from 428 to 1927 ng/mL (N = 7); after smoking, they ranged from 15,852 to 504,880 ng/mL (N = 7). Peak plasma cocaine concentrations after intravenous administration ranged from 122 to 442 ng/mL A = 7), and after smoking, concentrations ranged from 46 to 291 ng/mL A = 7). The thermal degradation product of cocaine, AEME, was detected in saliva but not in plasma after smoking. Peak saliva AEME concentrations were achieved at 2 min and ranged from 558 to 4374 ng/mL (N = 7). These are the first reported observations of heroin and metabolites in saliva following heroin smoking and of AEME in saliva after smoking cocaine base. The presence of AEME in saliva may be useful as a marker of the smoked route following cocaine administration.     

Drug-induced reinstatement to heroin and cocaine seeking: A rodent model of relapse in polydrug use.

The authors investigated several features of polydrug use in rats. Heroin and cocaine were self-administered following responses on different levers, with only 1 drug and 1 lever available on alternate days of training. Four doses of each drug (heroin: 25, 50, 100, and 200 μg/kg/infusion; cocaine: 0.25, 0.5, 1, and 2 mg/kg/infusion) were tested, and each rat was exposed to a single dose combination. Rats readily developed drug-specific and dose-related responding. During extinction, rats displayed a significant bias for responding on the cocaine-associated lever. Priming injections of either cocaine (20 mg/kg) or heroin (0.25 mg/kg) reinstated responding that was selective for the lever previously associated with each drug These results suggest that in this type of polydrug use, drugs have the capacity to activate drug-seeking behavior selectively oriented toward stimuli previously associated with their administration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Empirical assessment of the self-medication hypothesis among dually diagnosed inpatients

The aim of this study was to empirically determine the expected effects of drugs of abuse on the psychiatric symptoms of individuals dependent on alcohol and other drugs to assess the validity of the self-medication hypothesis, defined as motivation of patients to seek a specific drug for relief of a particular set of symptoms. Eight-three inpatients in a large metropolitan hospital with an axis I diagnosis of one drug dependence and an axis II diagnosis of personality disorder completed the Hopkins Symptom Checklist-Revised (HSCL-90-R) and the Neuropsychological Impairment Scale (NIS). They also reported the effect of their drug of choice on each of the symptoms included in both tests. Heroin addicts reported that heroin improved some of their psychiatric symptoms and all of their cognitive dysfunctions. Both cocaine and alcohol users reported that their drug of choice worsened their psychiatric and cognitive symptoms. No relationship was found between frequency or severity of symptoms and drug choice. We concluded that attempts at self-medication may have occurred among heroin addicts, but were unlikely among alcoholics and cocaine addicts. We found no evidence in support of the self-medication hypothesis as a necessary reinforcer of continued drug use.     

Antithrombotic agents in unstable angina. Review of clinical trials

The purpose of this experiment was to investigate the regulation of drug intake in rats (n = 20) self-administering heroin or cocaine during daily 5-hr sessions. Operant chambers were equipped with 2 levers and associated stimulus lights. A response on the lever with stimuli signaling an increase in dose size increased the infusion duration by 3 s, and a response on the lever with stimuli signaling a decrease in dose size decreased the infusion duration by 3 s. Results showed that daily and hourly drug intake for cocaine and heroin groups were relatively constant. Significant correlation coefficients were obtained for heroin and cocaine groups for the relationship between interdose interval (IDI) and infusion duration (dose size). These findings indicate that subjects regulated their drug intake by adjusting IDI throughout drug self-administration sessions.     

A novel paradigm to investigate regulation of drug intake in rats self-administering cocaine or heroin intravenously.

The purpose of this experiment was to investigate the regulation of drug intake in rats (n?=?20) self-administering heroin or cocaine during daily 5-hr sessions. Operant chambers were equipped with 2 levers and associated stimulus lights. A response on the lever with stimuli signaling an increase in dose size increased the infusion duration by 3 s, and a response on the lever with stimuli signaling a decrease in dose size decreased the infusion duration by 3 s. Results showed that daily and hourly drug intake for cocaine and heroin groups were relatively constant. Significant correlation coefficients were obtained for heroin and cocaine groups for the relationship between interdose interval (IDI) and infusion duration (dose size). These findings indicate that subjects regulated their drug intake by adjusting IDI throughout drug self-administration sessions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single- Versus Dual-Drug Target: Effects in a Brief Abstinence Incentive Procedure.

The number of drugs targeted may have an important influence on the ability of drug abusers to abstain during motivational incentive procedures. The authors investigated outcomes in methadone maintenance patients (n = 58), who had evidence of both opiate and cocaine use, when continuous abstinence from cocaine only (single target) or from both cocaine and heroin (dual target) was required to earn $200 in voucher incentives over a 4-day period. Study patients were equally likely to initiate and sustain abstinence from cocaine under the single- versus the dual-drug target. They were more likely to initiate opiate abstinence under the dual-target condition, demonstrating sensitivity to reinforcer effects. Results suggest that adding a second drug target does not impede short-term cocaine abstinence initiation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Smoked heroin and cocaine based (speedball) combinations in Rhesus monkeys.

The purpose of this investigation was to compare the self-administration of heroin and cocaine base, alone and in combination, in rhesus monkeys (Macaca mulatta) self-administering a combination of heroin (0.1 mg/kg/delivery) and cocaine base (1.0 mg/kg/delivery) via the smoking route. Smoke deliveries were contingent on completion of a chained fixed ratio (FR; lever press), FR 5 (inhalation) schedule. The lever press FR values (64, 128, 256, 512, and 1,024) represented increasing drug price. Demand functions (Consumption x Price) were obtained for the heroin and cocaine combination and compared with previously determined demand functions for smoked heroin and cocaine alone. As the FR increased and the number of responses emitted increased, the number of drug deliveries decreased. The demand functions were not different for heroin versus cocaine alone or for cocaine alone versus the cocaine-heroin combination. However, the demand for heroin alone was significantly less than the demand for the cocaine-heroin combination, suggesting that smoked cocaine base enhances the behavioral effects of smoked heroin. (PsycINFO Database Record (c) 2010 APA, all rights reserved)